PROJECT SUMMARY/ABSTRACT Stockdill, Jennifer L. The focus of the proposed research is the development of efficient methods for the construction of C-N bonds in the context of biologically active natural products and peptidic structures such as glycoproteins. There is significant demand for efficient syntheses of heterocyclic and peptidic structures because of their prevalence as pharmaceutical lead targets. The mentored K99 phase research will focus on the development of a methodology to access angularly-substituted decahydroquinolines. This method will enable rapid access to the recently isolated acetylcholinesterase inhibitor lycojapodine A. The independent R00 phase research will be centered on the use of nitrogen-centered radicals for new reaction methods. First, efforts will be directed toward a method for the formation of polycyclic structures containing a tertiary amine at a ring junction. This method will be utilized in the synthesis of the leuconicine family of alkaloids, which reverse vincristine resistance in KB cells. Additionally, a novel approach to the long-standing challenge of peptide ligation will be pursued. Together, the proposed methods will enable more efficient access to challenging architectures that are prevalent in natural products and will streamline the synthesis of homogeneous glycoproteins. Thus, the proposed research will improve access to important lead targets for the treatment of illnesses and to homogeneous versions of glycoproteins, which will enable studies of their function in cellular processes and diseases.